RMC unwinding-assertions should be on by default

[nchong-at-aws]

RMC should use --unwinding-assertions by default and have an option to disable the checks. The tool should suggest increasing loop bounds or disabling unwinding assertions if these assertions fail.

[adpaco-aws]

@danielsn suggested having a few flags on by default (--unwinding-assertions being one of them), and provide a new flag (e.g., --no-safe-options) to disable them manually.